US Patent 9041789 System and method for determining driver alertness

A driver alertness detection system includes an imaging unit configured to image an area in a vehicle compartment where a driver's head is located; an image processing unit configured to receive the image from the imaging unit, and to determine positions of the driver's head and eyes; and a warning unit configured to determine, based on the determined position of the driver's head and eyes as output by the image processing unit, whether the driver is in an alert state or a non-alert state, and to output a warning to the driver when the driver is determined to be in the non-alert state.